update-info-dir: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/sbin/update-info-dir - from package: install-info

You may install the required package with command apt-get install {package}

Error in other languages:
update-info-dir: bevel nie gevind nie
update-info-dir: comandă negăsită
update-info-dir: comando não encontrado
update-info-dir: commande introuvable
update-info-dir: command not found
update-info-dir: käsku ei ole
update-info-dir: không tìm thấy lệnh
update-info-dir: komanda nerasta
update-info-dir: Kommando nicht gefunden.
update-info-dir: kommandot finns inte
update-info-dir: komut yok
update-info-dir: nie znaleziono polecenia
update-info-dir: níor aimsíodh an t-ordú
update-info-dir: no se encontró la orden
update-info-dir: no s'ha trobat l'ordre
update-info-dir: opdracht niet gevonden
update-info-dir: parancs nem található
update-info-dir: perintah tidak ditemukan
update-info-dir: príkaz nenájdený
update-info-dir: příkaz nenalezen
update-info-dir: команда не найдена
update-info-dir: командата не е открита
update-info-dir: 命令找不到
update-info-dir: コマンドが見つかりません